The two most common pupusas are the pupusa de quesillo (cheese) and more popular pupusa mixta with mixed ingredients of cheese, beans,[1] and chicharrón. Pupusas are typically served with curtido (lightly fermented cabbage slaw with red chilies and vinegar).

Pupusas are similar to the South American arepa. The main differences are that pupusas are filled prior to cooking (while arepas, afterwards), and that pupusas are made from nixtamal, whereas arepas are made from ordinary corn dough. Nixtamal is basically the same corn dough, but it has undergone a preparation process involving an alkaline solution before cooking, which contributes to the peeling of the grains, making valuable nutrients available. This process was developed in Mesoamerica around 1500–1200 BCE. Early Mesoamericans used quicklime or slaked lime and ashes as the alkaline solution. Dried nixtamal is now commercially available.

The Mexican gordita is also similar to the Salvadoran pupusa, but the ingredients vary. Gorditas generally have more filling than pupusas (hence the name gordita—"little fatty") and normally have an opening at the center of the tortilla.

Traditional pupusas in El Salvador are cooked over wood fire, using a pottery griddle (called a comal).

Pupusas were first created centuries ago by the Pipil tribes who inhabited the territory now known as El Salvador. Cooking implements for their preparation have been excavated in Joya de Cerén, "El Salvador's Pompeii", site of a native village that was buried by ashes from a volcano explosion, and where foodstuffs were preserved as they were being cooked almost 2000 years ago. The instruments for their preparation have also been found in other archaeological sites in El Salvador.

In the late 1940s, pupusas were still not widespread across El Salvador, and were mostly localized in the central towns, such as Quezaltepeque, and cities of the country. As the population began migrating to other areas in the 1960s, pupusa stands proliferated across the country and in neighboring areas of Honduras and Guatemala, sometimes with variations in shape, size or filling. In Guatemala during the 1970s, pupusas had a half-moon shape. The half-moon shape would be considered a half-eaten pupusa in the Chalatenango area; fish pupusas were uncommon, and pupusas served east of the Lempa River usually had a much larger diameter.

In the 1980s, the Salvadoran civil war forced a Salvadoran migration to other countries, mainly the United States. Therefore, pupusas became available outside the country wherever a Salvadoran community was found. Immigrants have brought the dish to most areas of the United States. One example is Los Angeles, California, where there are now many pupuserías (where pupusas are made and sold). Pupuserías also may be found in many areas of Canada. In recent years, pupusas can even be found in some Latin American restaurants in Adelaide,[2]Melbourne and Sydney in Australia.

Both at home and abroad, pupusas are traditionally served with curtido (a pickled cabbage relish, analogous to German Sauerkraut and Korean kimchi that comes in mild and spicy varieties) and tomato sauce, and are traditionally eaten by hand.

Many local folklore tales surround the dish; they often tell of diverse origins or effects of pupusas on people.

A variant of the pupusa in El Salvador is the pupusa de arroz. Rice flour is used to make the dough and they are usually stuffed with chopped pork, cheese, beans, zucchini, and other vegetables. They hail from the town of Olocuilta, located to the east of San Salvador, but are now readily available throughout the country. Another regional variation, found in Alegría, is the pupusa de banano, which calls for the addition of plantain bananas to the pupusa.

Pupusas made in the United States are typically made with Maseca (brand) commercial corn flour-masa mix) instead of fresh masa harina. Some high-end pupuserías in the United States use rice flour and wheat flour versions.

In Santa Fe, New Mexico, variations include using spinach, pepperoni, cheese, and green chile.

A similar Mexican dish is called a gordita (literally, "little fatty"), but gorditas are usually open at one end. In Venezuela, they make arepas (where the dough is cooked first, and then sliced in half and stuffed somewhat like a hamburger). Colombia has its own recipe of arepas, but, unlike Venezuelan, Colombian arepas are usually eaten without filling, or the filling is placed inside the dough before cooking. Pupusas are also found in neighboring Central American countries. Honduran versions often use the local quesillo type of cheese for the filling. In Costa Rica, both "Salvadoran pupusas" and "pupusas" are available, the latter being a local version. There, they are a staple of the food stalls at regional carnivals known as fiestas.

In spite of their low market price, pupusas represent an important element in the economy of El Salvador. In addition to whole pupusas, the individual ingredients are also exported; in 2005 for example, US$604,408 worth of loroco was sold to the United States alone.[citation needed] Frozen pupusas can be found in the refrigerated section of many Hispanic and international supermarkets in the United States, especially ones that are located in highly concentrated areas of El Salvadorans such as Washington, D.C..